Process of degreasing the meal used in cleaning tin plate



Patented Apr. 15, 1924.

SAMUEL PIEAOOCK, OF WHEELING, WEST VIRGINIA, ASSIGNOB T0 WHEELING STEEL&

IRON COMPANY, OF WHEELING, WEST VIRGINIA,

GINIA.

A CORPORATION OF VIR- PROCESS OF DEGREASING- THE MEAL USED IN CLEANING-TIN PLATE.

No Drawing.

To all whom it may concern:

Be it known that I, SAMUEL PEACOOK, a citizen of the United States,residing at Wheeling, in the county of Ohio and State of West Virginia,have invented certain new and useful Improvements in Processes ofDegreasing the Meal Used in Cleaning Tin Plate; and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

This invention relates to a process of recovering the flour middlings ormeal now commonly used in absorbing the palm oil employed on tin plateduring their manufacture and has for its object to provide a procedurewhich will be less expensive and more efficient than those heretoforeproposed.

With these and other objects in view, the invention consists in thenovel steps and combinations of steps constituting the process, all aswill be more fully hereinafter disclosed and particularly pointed out inthe claims.

In order that the precise invention may be the better understood, it issaid:

In the manufacture of tin plate, the steel sheets that come from thebath of molten tin pass first through a bath of molten palm oil for thepurpose of forming a film of oil thereon to protect the surface of thetin from contact with the air, while it is hot, the object being toprevent any surface oxidation of the tin.

After the tin is cooled below its oxidation temperature, it is a commonpractice to remove this oil by subjecting the coated sheets to a rubbingaction with a low grade flour product known as middlings or meal. Thismaterial readily absorbs the palm oil and leaves the tin surfaces clean.But the meal becomes in time so saturated with the palm oil that it canno longer be used for cleaning plates, and then it is discarded or soldfor stock food and other purposes.

On the other hand, if these middlings could be thoroughly degreased andthe oil recovered, they could be used over and over again, theiroriginal cost thus saved, and the oil returned to the process. It hasbeen proposed to recover this said meal or middlings by treating themwith a solvent such Serial Ho. 535,961.

as naptha. But it has been found that solvents such as naptha, gasoline,etc, contain some residual oils of relatively high boiling points thatcan only be removed by treating the meal with steam, or by heating saidmeal to a temperature suificiently high to drive off such oils. But itis found that the use of steam causes a hydrolysis of the starchymatters in the meal, thus destroying its oil absorbing qualities; and ithas also been found that the driving off of the residual oils by heatlikewise destroys the useful properties of this said meal.

It is further found in practice that this oil saturated meal whentreated with any solvents tried, contains numerous smallparticles orknots that remain saturated with the oil no matter how long the saidsolvent and meal is stirred together, so that only the objectionablesteam or heat above mentioned has prior to this invention been foundeffective in entirely removing the last portions of the palm oil.

According to this invention, on the other hand, I overcome the aboveobjections by proceeding as follows:

I treat these saturated middlings with a purified benzol. I have furtherfound that when these saturated middlings are suspended in this solvent,and beaten for a considerable time, say two or three hours, in asuitable beating engine such as is used in making paper pulp, forexample, such a complete contact between the knots of saturatedmiddlings and solvent is efl'ected that when the mass thus treated issubjected to filter pressing, or to other separating apparatus adaptedto remove the solvent a complete extraction of the palm oil is effected.

The benzol and palm oil having now been separated from the meal, thelast traces of said benzol may be eliminated by subjecting the mass to arelatively low temperature of, say, 50 C. or C. in a vacuum of, sa 20 to25 inches of mercury, after which the meal will be found to be restoredto its original clean condition. The palm oil dissolved in the benzol,as well as the benzol itself are readily recovered by any suitable andwell known methods.

It is important in carrying out this process that the meal is kept freefrom contact with water to prevent hydrolysis of the same, and that thebenzol is extracted out of contact With air to. prevent dangerousmixtures of the same with air.

It is obvious that those skilled in the art may vary the details of theprocedure Without departing from the spirit of the invention, andtherefore, I do not Wish to be limited to the above disclosure except asmay be required by the claims.

What'is claimed is 1. The process of degreasing meal used in removingpalm oil from tin plate which consists in mixing benzol with said meal;subjecting said mixture to the action of a beating engine until all thepalm oil has been dissolved from said meal; and freeing said meal fromsaid benzol, substantially as described. V

2. The process of degreasing meal used in removing palm oil from tinplate which consists in mixing benzol With said meal; subjecting saidmixture to the action of a beat-ii engine until all the pa m oil hasbeen dissolved from said meal; cing said meal from said benzol,comprising the subjection of said meal to the action of a ilter press,and to a temperature below that at Whichthe absorbent qualities of saidmeal are injured, substantially as described.

3, The process of degreasing meal used in removing palm. oil from tinplate Which consists in mixing benzol With said meal; subjecting saidmixture to the action of a beating engine until all the palm oil hasbeen dissolved fronr said meal; and tree ing said meal from said benzolby first separating a substantial portion of said ben- 201 from saidmeal, then heating the. mass and subjecting it to suction, substantiallyas described.

In testimony whereof I alfix my signature.

SAMUEL PE ACOCK.

